Magnetic perm eameter



n e.. h S .fu e nu h S 2 l G N 0 DW. D.. S D S. o@ P A N K. D B .u d Mm o m.

MAGNETIC: PBRMEAMETER.

/N VEN 70H5 A TTOHNE YS.

(No Model.) l '-ZISheets-Y-Sheet 2'.

E. D. KNAP 8v S.- D. SPRONG.

MAGNBTIG PERMBAMBTER.

10.508,827. '#Paitentedlvom 14, 1893;

' /6 a" 'J9 l i I if y' l :f f. :jij r 'AN v *i* /H .71 I 1, I 10 j: 77

w/TNEssEs: /NvE/vros A Tron/v5 rs.

EDGAR 'DAY KNAP, OF

' Y UNITED STATnsyPATENT OFFICE.

lNEw' YORK.v

MAG N-ETI-C PE EAMETER.

SPECIFICATION forming part of Letters Patent No. 508,827, dated November 14, 1893.

`Application led .Tune 28, 1893.

' the annexed drawings, forming a part'thereof, in which- A Figure 1 is afront elevation of our improved magnetic permeameter. Fig. 2 is a vertical transverse section, taken on line'2v-2 in Fig. l.

i Fig. 3 is an inverted plan view, with the bottom of the casing'- removed. Fig. 4 isa horizontal section taken on line 4.-4 in Fig. 1. Fig. 5 is a vertical transverse section taken on line 5-5 in Fig. 3. A

Similar gures and letters of reference indicate corresponding parts in all the views.

The object of our invention is to construct p an instrument by means of which the magnetic permeability of a body of iron may lbe readily determined, the instrument being especially designed for testing iron used in the construction of dynamos and motors, more particularly in the field magnets of such machines.

Our invention consists in the combination with the eld magnet having obliquel pole pieces, of a soft iron armature arranged to turn between the pole pieces and having oblique wings or arms, the oblique pole pieces beingarrangeddiagonallyopposite each other, the wings of the armature being also arranged diagonally opposite each other to A avoid a magnetic short circuit in the instrument. It also lconsists in polar extensions formed on or attached to the poles'of the field magnet, for forming contact with the iron to be tested, all as will be hereinafter more fully described.

In carrying out our invention, we employ a magnetic shunt in which one branch is an armature in the field of a magnet, the other branch being through polar extensions of the magnet and the iron to be measured. The instrument is designed to work by the balance of the shunt, including the iron to be measured, the pull of the magnet on the armature being opposed by a spring insuch a manner that when the field of the instrument sel-innamaovz. na man.)

is weakened by the flux of magnetic force through the iron (to be measured) composing the shunt, the armature will change its position,the movement ofthe armature being indicated bya suitable index. This movement will be proportional to the ux through the sonENEorADY, AND sEvERN D.r sPRoNe, oF EAST 'GREENeUsI-i, Y

shunt, and the flux through theshunt will be proportional to the quality of the iron forming the'shunt.

The field magnet 10 is provided with pole pieces 1l attached to or formed upon the polar extremities of the magnet, and a portion of each pole piece projects inwardly and is out 0E obliquely, the inwardly-extending oblique portions being arranged diagonally opposite each other. ln Vthe center of the space between the pole pieces 11, is journaled an arbor 15, on which is mounted a sleeve 14:, to the ends of which are attached the Wings 13 of the armature. The said wings' are made of soft iron, as is also the sleeve 11i-each of the wings to be in the form of a segment of a hollow truncated cone, each segment comprising about ninety degrees. The said wings 13 are arranged diagonally opposite each other, and are fitted to revolve near but not in contact with the pole pieces 11. The concave faces of the pole pieces opposite the wings of the armature are of conical form, and of about the same shape and extent as the outer faces of the armature wings. Y

On the arbor 15 is mounted an index 17, which moves in front of `a scale 18 attached to the top of the magnet 10, and to thesaid arbor is secured the inner end of a volute spring 19, the outer end of which is attached to the inner end of a lever 20, the said end of the said spring being inserted in a slit e in the arm d, of the said lever. The lever 2O is journaled on a boss on the'inner face of one of the bars 16, whichis attached to the pole piece 11 of the magnet and supports one of the bearings of the arbor 1.5. The outerend of the lever 2O projects beyond vthe bar 16, Where it may be readily grasped when it is desired to adjust the instrument.

The magnet 10 is provided'with polar extensions 12, which are for the purpose of forming a magnetic contact with the body of iron to be tested. The pull of the magnet on the armature is opposed by the spring 19, and

the said spring is adjusted so as to hold the lndex 17 and the armature normally in the zero position. When the polar extremities 12 are placed upon or in magnetic contact cned, thereby releasing the armature in proportion to the diminution of the magnetic strength, allowing the volute spring 19 to carry the wings 13 more or less out of the ield of force. cated by the index 17 on the scale 18, it shows the degree of magnetic permeability of the body of iron being tested. By the diagonal arrangement of the pole pieces and ot' the a-rmature win gs, the greatest possible deiiection is secured without creating a magnetic short circuit by anything short of a deflectionof one hundred and eighty degrees.

To` insure the greatest possible accuracy, the` pivots b of the arbor 15 are journaled in jeweled bearings ct a', supported in the bars 16; and to protect the instrument from injury and dust, it is inclosed in a casing 21, having the front end closed by a glass window 22.

Having thus described our invention, We claim as new and desire to secure by Letters Patentl 1. A magnetic permeameter, formed of a field magnet having polar extensions for contact with the metal to be tested, an armature pivotally supported within the tield of the magnet, and a spring for opposing the pull of themagnet on the armature, substantially as specified.

` 2. Amagnetic permeameter, consisting of a ield magnet-,an armature pivotally supported Within the field of the magnet, the magnet and armature with the metal to 'be tested forming a shuntmagnetic circuit in which the metal to be tested is `in one branch, the armature being in the other branch, substantially as specified.

3. In a magnetic permeameter, a magnet having polar extensions of reduced diameter for localizing the magnetic action of the; instrument, substantially as herein specified.

4,. A magnetic permeameter, wherein a movable armature forms one branch of a mag- When this amount is indi-- netic shunt, and in which the metal to be tested. forms the other branch of the magnetic shunt, as'herein specified.

5. A magnetic permeameter, formed of a field magnet having oblique pole pieces, an armature having two wingsv formed of segments of the frustum of a truncated hollow cone and oppositely arranged with respect to each other, and a spring attached to the armature and arranged to oppose the pull of the magnet on the 'armature, substantially as specified.

6. A magnetic permeameter, formed of a field magnet having oblique pole pieces, an armature having two wings formed of segments of the frustum of a truncated hollow cone and oppositely arranged with respect to each other, a spring attached to the armature.

an index carried by the armature arbor, and a fixed scale arranged for use in connection with the index, substantially as specified.

7. In a permeameter, the combination of a Iieldmagnet provided with polar extensions for contacting with the iron Vto be measured,

a soft iron armature placed between poles of l the magnet, a spring for opposing the turning of the armature, and means for indicating the motion ot' the armature, substantially as specified. A

8. The combination wit-h a tield magnety provided with pole pieces and polar extensions projecting from the pole pieces, offa pivoted armature between the pole pieces, having convex faces that are diagonal to the axis of the armature and conformto concave faces of the pole-pieces, an indicating hand, an opposing spring, and a graduated scale, substantially as specified.

9. The combination, with a field magnet provided with pole-pieces and polar extensions projecting from the pole pieces, of a pivoted armature between the pole pieces, having convex faces that are diagonal to the axis of the armature and conform to concave faces on the pole-pieces, an indicating hand, an opposing spring, a regulator for the spr-ing, and a graduated scale, substantially asspe'ciied.

vEDGAR DAY KNAP.

SE'VERN D. SPRONG..

Vitnesses:

N. WILSON, EDWIN C. BELDEN. 

